1. Field of the Invention
The invention generally relates to films of nano materials and methods for making the same, particularly, to a carbon nanotube film structure and a method for making the same.
2. Discussion of Related Art
Carbon nanotubes (CNTs) produced by means of arc discharge between graphite rods were discovered and reported by Sumio Iijima in 1991. CNTs are electrically conductive along their length, chemically stable, and each can have a very small diameter (much less than 100 nanometers) and large aspect ratios (length/diameter). Due to these and other properties, it has been suggested that CNTs can play an important role in manufacturing filters.
Applications of carbon nanotubes are rather restricted due to the carbon nanotubes made by the conventional method being generally grainy or powdery in macrostructure. Therefore, more and more attention is being given to develop new and various carbon nanotube macrostructures.
A conventional method for making a carbon nanotube film structure includes the following steps. Firstly, providing a growing substrate. Secondly, forming a catalyst layer on the growing substrate. Thirdly, providing a reacting furnace, and placing the growing substrate with catalyst layer into the reacting furnace. Finally, introducing a carbonaceous gas and heating the reacting furnace to grow carbon nanotube film structure. The carbon nanotube film structure made by the above-described method is formed on the growing substrate and includes a plurality of carbon nanotubes. The carbon nanotubes are entangled with each other and distribute in the carbon nanotube film structure disorderly.
However, some drawbacks arise from the conventional carbon nanotube film structure and method for making the same. Firstly, due to the carbon nanotubes in the carbon nanotube film structure being entangled with each other and distributed in a disorderly manner, the excellent properties of the carbon nanotubes are poorly utilized. Secondly, applications of the carbon nanotube film structure are restricted because the carbon nanotube film structure is not a free-standing structure and must be formed on a substrate. Thirdly, the method introduces catalysts into the carbon nanotube film structure during the forming process, thereby reducing the purity of the carbon nanotube film structure. Fourthly, it is hard to recycle the substrate for use in mass production.
What is needed, therefore, is a carbon nanotube film structure with high purity and a method for making the same.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one present embodiment of the carbon nanotube film structure and the method for making the same, in at least one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.